/*
   * Copyright(c) 2007 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Maintained at www.Open-FCoE.org
   */
  
  #ifndef _FC_FRAME_H_
  #define _FC_FRAME_H_
  
  #include <linux/scatterlist.h>
  #include <linux/skbuff.h>
  #include <scsi/scsi_cmnd.h>
  
  #include <scsi/fc/fc_fs.h>
  #include <scsi/fc/fc_fcp.h>
  #include <scsi/fc/fc_encaps.h>
  
  #include <linux/if_ether.h>
  
  /* some helpful macros */
  
  #define ntohll(x) be64_to_cpu(x)
  #define htonll(x) cpu_to_be64(x)
  
  static inline u32 ntoh24(const u8 *p)
  {
  	return (p[0] << 16) | (p[1] << 8) | p[2];
  }
  
  static inline void hton24(u8 *p, u32 v)
  {
  	p[0] = (v >> 16) & 0xff;
  	p[1] = (v >> 8) & 0xff;
  	p[2] = v & 0xff;
  }
  
  /*
   * The fc_frame interface is used to pass frame data between functions.
   * The frame includes the data buffer, length, and SOF / EOF delimiter types.
   * A pointer to the port structure of the receiving port is also includeded.
   */
  
  #define	FC_FRAME_HEADROOM	32	/* headroom for VLAN + FCoE headers */
  #define	FC_FRAME_TAILROOM	8	/* trailer space for FCoE */
  
  /* Max number of skb frags allowed, reserving one for fcoe_crc_eof page */
  #define FC_FRAME_SG_LEN		(MAX_SKB_FRAGS - 1)
  
  #define fp_skb(fp)	(&((fp)->skb))
  #define fr_hdr(fp)	((fp)->skb.data)
  #define fr_len(fp)	((fp)->skb.len)
  #define fr_cb(fp)	((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
  #define fr_dev(fp)	(fr_cb(fp)->fr_dev)
  #define fr_seq(fp)	(fr_cb(fp)->fr_seq)
  #define fr_sof(fp)	(fr_cb(fp)->fr_sof)
  #define fr_eof(fp)	(fr_cb(fp)->fr_eof)
  #define fr_flags(fp)	(fr_cb(fp)->fr_flags)
  #define fr_encaps(fp)	(fr_cb(fp)->fr_encaps)
  #define fr_max_payload(fp)	(fr_cb(fp)->fr_max_payload)
  #define fr_fsp(fp)	(fr_cb(fp)->fr_fsp)
  #define fr_crc(fp)	(fr_cb(fp)->fr_crc)
  
  struct fc_frame {
  	struct sk_buff skb;
  };
  
  struct fcoe_rcv_info {
  	struct fc_lport	*fr_dev;	/* transport layer private pointer */
  	struct fc_seq	*fr_seq;	/* for use with exchange manager */
  	struct fc_fcp_pkt *fr_fsp;	/* for the corresponding fcp I/O */
  	u32		fr_crc;
  	u16		fr_max_payload;	/* max FC payload */
  	u8		fr_sof;		/* start of frame delimiter */
  	u8		fr_eof;		/* end of frame delimiter */
  	u8		fr_flags;	/* flags - see below */
  	u8		fr_encaps;	/* LLD encapsulation info (e.g. FIP) */
  	u8		granted_mac[ETH_ALEN]; /* FCoE MAC address */
  };
  
  
  /*
   * Get fc_frame pointer for an skb that's already been imported.
   */
  static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  {
  	BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
  	return (struct fcoe_rcv_info *) skb->cb;
  }
  
  /*
   * fr_flags.
   */
  #define	FCPHF_CRC_UNCHECKED	0x01	/* CRC not computed, still appended */
  
  /*
   * Initialize a frame.
   * We don't do a complete memset here for performance reasons.
   * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
   */
  static inline void fc_frame_init(struct fc_frame *fp)
  {
  	fr_dev(fp) = NULL;
  	fr_seq(fp) = NULL;
  	fr_flags(fp) = 0;
  	fr_encaps(fp) = 0;
  }
  
  struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
  struct fc_frame *_fc_frame_alloc(size_t payload_len);
  
  /*
   * Allocate fc_frame structure and buffer.  Set the initial length to
   * payload_size + sizeof (struct fc_frame_header).
   */
  static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
  {
  	struct fc_frame *fp;
  
  	/*
  	 * Note: Since len will often be a constant multiple of 4,
  	 * this check will usually be evaluated and eliminated at compile time.
  	 */
  	if (len && len % 4)
  		fp = fc_frame_alloc_fill(dev, len);
  	else
  		fp = _fc_frame_alloc(len);
  	return fp;
  }
  
  /*
   * Free the fc_frame structure and buffer.
   */
  static inline void fc_frame_free(struct fc_frame *fp)
  {
  	kfree_skb(fp_skb(fp));
  }
  
  static inline int fc_frame_is_linear(struct fc_frame *fp)
  {
  	return !skb_is_nonlinear(fp_skb(fp));
  }
  
  /*
   * Get frame header from message in fc_frame structure.
   * This version doesn't do a length check.
   */
  static inline
  struct fc_frame_header *__fc_frame_header_get(const struct fc_frame *fp)
  {
  	return (struct fc_frame_header *)fr_hdr(fp);
  }
  
  /*
   * Get frame header from message in fc_frame structure.
   * This hides a cast and provides a place to add some checking.
   */
  static inline
  struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
  {
  	WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
  	return __fc_frame_header_get(fp);
  }
  
  /*
   * Get source FC_ID (S_ID) from frame header in message.
   */
  static inline u32 fc_frame_sid(const struct fc_frame *fp)
  {
  	return ntoh24(__fc_frame_header_get(fp)->fh_s_id);
  }
  
  /*
   * Get destination FC_ID (D_ID) from frame header in message.
   */
  static inline u32 fc_frame_did(const struct fc_frame *fp)
  {
  	return ntoh24(__fc_frame_header_get(fp)->fh_d_id);
  }
  
  /*
   * Get frame payload from message in fc_frame structure.
   * This hides a cast and provides a place to add some checking.
   * The len parameter is the minimum length for the payload portion.
   * Returns NULL if the frame is too short.
   *
   * This assumes the interesting part of the payload is in the first part
   * of the buffer for received data.  This may not be appropriate to use for
   * buffers being transmitted.
   */
  static inline void *fc_frame_payload_get(const struct fc_frame *fp,
  					 size_t len)
  {
  	void *pp = NULL;
  
  	if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
  		pp = fc_frame_header_get(fp) + 1;
  	return pp;
  }
  
  /*
   * Get frame payload opcode (first byte) from message in fc_frame structure.
   * This hides a cast and provides a place to add some checking. Return 0
   * if the frame has no payload.
   */
  static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
  {
  	u8 *cp;
  
  	cp = fc_frame_payload_get(fp, sizeof(u8));
  	if (!cp)
  		return 0;
  	return *cp;
  
  }
  
  /*
   * Get FC class from frame.
   */
  static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
  {
  	return fc_sof_class(fr_sof(fp));
  }
  
  /*
   * Check the CRC in a frame.
   * The CRC immediately follows the last data item *AFTER* the length.
   * The return value is zero if the CRC matches.
   */
  u32 fc_frame_crc_check(struct fc_frame *);
  
  static inline u8 fc_frame_rctl(const struct fc_frame *fp)
  {
  	return fc_frame_header_get(fp)->fh_r_ctl;
  }
  
  static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
  {
  	return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
  }
  
  /*
   * Check for leaks.
   * Print the frame header of any currently allocated frame, assuming there
   * should be none at this point.
   */
  void fc_frame_leak_check(void);
  
  #endif /* _FC_FRAME_H_ */